Continuous flow mixing apparatus

ABSTRACT

A continuous flow liquid mixing apparatus in which a rotor is arranged coaxially within a housing with the mutually facing peripheral surfaces thereof defining a clearance space in the form of an annular passage with a gradually and continuously decreasing radial cross-section. This annular passage serves as a mixing zone having an inlet opening at the larger section end and an outlet opening at the smaller section end thereof. The mutually facing peripheral walls of the rotor and housing are continuous and smooth and free of any interruptions or perforations and preferably the radial dimension of the clearance space is not more than 10 mm and optimally not more than 5 mm. Drive means are provided for imparting relative rotation to the rotor or housing to apply shearing forces to liquid passing through the mixing zone. In the region upstream of the mixing zone, the mutually facing peripheral wall sections of the rotor and housing diverge sharply to provide a feeding space which is free of interruptions in the form of baffles, grooves or the like and the liquid or liquids to be mixed are introduced into this feeding space.

[ 1 Aug. 27, 1974 1 CONTINUOUS FLUW NG APP [75] Inventor:

Frans Henri Claes, Edegern, Belgium [30] Foreign Application Priority Data Mar. 4, 1970 Great Britain 15950/70 Mar. 4, 1970 Great Britain 15948/70 [52] US. Cl. 259/7, 23/252 R [51] Int. Cl 301i 7/08 [58] Field of Search 259/7, 8, 23, 24, 43, 44; 23/252 [56] References Cited UNITED STATES PATENTS 2,858,083 10/1958 Shurts 259/8 2,969,960 1/1961 Gurley 259/7 2,995,346 8/1961 Samples 259/8 3,102,717 9/1963 Frenkel I 259/7 3,417,969 12/1968 Meskat 259/7 3,420,506 1/1969 Gurley 259/8 Primary Examiner-Robert W, Jenkins Attorney, Agent, or FirmWilliam J. Daniel ABSTRACT A continuous flow liquid mixing apparatus in which a rotor is arranged coaxially within a housing with the mutually facing peripheral surface-s thereof defining a clearance space in the form of an annular passage with a gradually and continuously decreasing radial crosssection. This annular passage serves as a mixing zone having an inlet opening at the larger section end and an outlet opening at the smaller section end thereof. The mutually facing peripheral walls of the rotor and housing are continuous and smooth and free of any interruptions or perforations and preferably the radial dimension of the clearance space is not more than 10 mm and optimally not more than 5 mm. Drive means are provided for imparting relative rotation to the rotor or housing to apply shearing forces to liquid passing through the mixing zone. In the region upstream of the mixing zone, the mutually facing peripheral wall sections of the rotor and housing diverge sharply to provide a feeding space which is free of interruptions in the form of baffles, grooves or the like and the liquid or liquids to be mixed are introduced into this feeding space.

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1. A continuous flow liquid mixing apparatus which comprises a central inner rotor and an outer housing surrounding the peripheral surface of the rotor, said housing and rotor being arranged coaxially to define therebetween a clearance space in the form of an annular passage having a cross-section continuously and gradually decreasing in radial dimension, said annular passage serving as a mixing zone having an inlet opening at the larger end thereof and an outlet opening at the smaller end thereof, the mutually facing peripheral walls of said rotor and housing defining said annular passage being continuous and smooth and free of interruptions or perforations, means for imparting to said rotor and housing relative rotational movement about their axis to apply shearing forces to the liquid flowing through said mixing zone, the mutually facing peripheral wall sections of said rotor and housing diverging sharply in the region upstream of said mixing zone inlet opening and being free of interruptions, and means for introducing at least one liquid to be mixed into said upstream region whereby all such liquids are introduced uniformly and homogeneously into said mixing zone.
 2. An apparatus according to claim 1 wherein the housing extends above said rotor generally parallel to the axis of revolution and said rotor tapers inwardly toward said axis to define said sharply diverging wall sections.
 3. An apparatus according to claim 1 wherein the internal periphery of the housing and the external periphery of the rotor taper towards said outlet opening.
 4. An apparatus according to claim 3 wherein the internal periphery of the housing and the external periphery of the rotor are conical.
 5. An apparatus according to claim 1 wherein the rotor is arranged for rotation and the housing is non-rotatable.
 6. An apparatus according to claim 5 wherein the rotor has an axially extending shaft by means of which it can be coupled to a motor.
 7. An apparatus according to claim 5 wherein the upper end of said rotor has a generally inverted conical shape.
 8. An apparatus according to claim 1 wherein said axis is vertical.
 9. An apparatus according to claim 1 wherein the maximum annular radius in said mixing zone is 10 mm.
 10. An apparatus according to claim 9 wherein the maximum annular radius is not more than 5 mm.
 11. An apparatus according to claim 1 wherein the mean diameter of the annular passage defining said mixing zone in any plane normal to the axis of relative rotation of the rotor and housing is substantially less than the axial length of said zone measured from the inlet to the outlet openings thereof.
 12. An apparatus according to claim 11 wherein the axial length of the mixing zone is at least 1.25 as large as its mean diameter.
 13. An apparatus according to claim 1 wherein the clearance between the inner wall of the housing and the outer wall of the rotor is from 10 mm to 0.01 mm.
 14. An apparatus according to claim 1 wherein a plurality of inlet pipes terminate in the sharply divergent region of said rotor and housing walls to introduce plural liquids to be mixed.
 15. A continuous flow liquid mixing method which comprises the steps of: a. passing at least one liquid to be mixed through a mixing zone having the form of an annular passage defined between the mutually facing peripheral surfaces of a housing and a rotor arranged coaxially within the housing, said surfaces being continuous and smooth and free of interruptions or perforations, said zone gradually and continuously decreasing in radial cross-section from an inlet opening to an outlet opening, and b. imparting relative rotational movement to the surfaces defining said zone at a speed sufficient to create a turbulent flow condition in the liquid passing through said zone.
 16. The method according to claim 15 wherein the mutually facing surfaces of said housing and rotor diverge sharply upstream of said mixing zone to define a feeding zone free of interruptions or obstructions and including the step of supplying plural liquids to be mixed into said feeding zone. 